Heat Exchanger: An Introduction To Heat Exchanger

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Introduction to heat exchangers Before the process of selecting the correct heat exchanger is initiated it is of critical importance to form an understanding of the types of heat exchanger on the market and the merits/down sides to each of the aforementioned devices. This section of the report aims to provide a fundamental understanding of flow regimes and an introduction to various heat exchanger configurations. In layman’s terms a heat exchanger is a device used to aid in the transfer of heat from one fluid medium to another. The fluids in question may be separated by a solid wall or may be free to mix as is the case in some applications. The surface area of the wall is maximised in a manner which tends to minimize disruption to the flow of the fluids. As is the case in some heat exchanger applications, fins or a form of corrugation may be used to induce turbulence and increase surface area. Heat exchangers have a wide and varied list of applications in both an industrial and in a domestic sense, these applications range from a heat exchanger used in chemical processing to the fridge in your kitchen. Heat exchangers fall in to 3 flow arrangements (in which there is subdivisions due to the physical make-up of the product).The heat exchanger flow arrangements being; Counter flow, parallel flow and cross flow. “In the counter-flow exchanger, the fluids enter the exchanger from opposite sides. This is the most efficient design because it transfers the greatest amount of heat. In the parallel-flow version, the fluids come in from the same end and move parallel to each other as they flow to the other side. The cross-flow heat exchanger moves the fluids in a perpendicular fashion.” (Wisegeek.com, 2014). Cross flow heat exchangers are... ... middle of paper ... ... has a satisfactory outcome. With capital cost and overall efficiency being the most prevalent criterion when selecting heat exchangers, engineers or indeed members of the general public oft times purchase and commission heat exchangers with this narrow minded mind-set. The provision for future plant/process expansion and maintenance should be a paramount when selecting a heat exchanger. Any heat exchanger should facilitate easy maintenance, thusly increasing system performance and the product life cycle. The old adage that you should over spec your heat exchanger bears merit in that it is nigh on impossible to recover from the short-comings associated with under-sizing a heat exchanger and an over specced heat exchanger allows for any increases in demand that may occur on a heat exchanger as well as compensating a degradation of HX performance over time.

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